Once he was placed into an in-ring role, Cena began using a semi-robotic character known as The Prototype.On October 10, 2000, while billed as The Prototype, Cena made his unofficial debut for the then World Wrestling Federation (WWF) on a Smack Down!, when Cena and A-Train defeated Undertaker and Orlando Jordan in a tag team match.Cena then pursued the United States Championship, but lost to then champion Eddie Guerrero in a Latino Street Fight for the title.
He received another tryout on January 9, 2001 at a Smack Down!
Cena started his professional wrestling career in 1999 with Ultimate Pro Wrestling (UPW) and won the UPW Heavyweight Championship the following year.
Cena signed a developmental contract with the World Wrestling Federation (WWF, later renamed to World Wrestling Entertainment, or simply WWE) in 2001, debuting on the WWE main roster in 2002.
From a generic character in 2002, Cena morphed into a rapper for the time period of 2002–2004, which earned him fame within the audience on Smack Down!
an accomplishment only previously achieved by WWE Hall of Famer Ric Flair.
Cena has the fourth-highest number of combined days as WWE Champion, behind Bruno Sammartino, Bob Backlund and Hulk Hogan. He has starred in the feature films The Marine (2006), 12 Rounds (2009), Legendary (2010), The Reunion (2011), Trainwreck (2015) and Sisters (2015).